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71.
We have developed a portable device for formaldehyde monitoring with both high sensitivity and high temporal resolution, and carried out indoor air formaldehyde concentration analysis. The absorbance difference of the sensor element was measured in the monitoring device at regular intervals of, for example, one hour or 30 min, and the result was converted into the formaldehyde concentration. This was possible because we found that the lutidine derivative that was formed as a yellow product of the reaction between 1-phenyl-1,3-butandione and formaldehyde was stable in porous glass for at least six months. We estimated the reaction rate and to be 0.049 min−1 and the reaction occurred quickly enough for us to monitor hourly changes in the formaldehyde concentration. The detection limit was 5 μg m−3 h. We achieved hourly formaldehyde monitoring using the developed device under several indoor conditions, and estimated the air exchange rate and formaldehyde adsorption rate, which we adopted as a new term in the mass balance equation for formaldehyde, in one office. 相似文献
72.
73.
The conductance of potassium iodide has been measured in the solvents ethylene carbonate, water, methyl ethyl ketone, and pairwise mixtures of these solvents at 40°C; and ethylene carbonate-water, tetramethylene sulfone-water, dimethyl sulfoxide-water, tetrahydrofuran-water, ethylene carbonate-tetramethylene sulfone-water, ethylene carbonate-tetramethylene sulfone, and tetrahydrofuran-dimethyl sulfoxide at 25°C. For dielectric constants greater than about 60, the pairing constants KA are in the range 0.3–2.0; no correlation between KA and solvent properties could be established. For lower dielectric constants, KA increases exponentially with decreasing dielectric constant. Addition of a proton, acceptor to water initially decreases KA regardless of whether the dielectric constant of the mixture is higher or lower than that of water, suggesting that ion pairs in water may be stabilized by cage structures. The Walden product Ao is also decreased by the addition of proton acceptors. 相似文献
74.
Direct photoetching of single crystal SiC by VUV-266 nm multiwavelength laser ablation 总被引:1,自引:0,他引:1
J. Zhang K. Sugioka S. Wada H. Tashiro K. Toyoda 《Applied Physics A: Materials Science & Processing》1997,64(4):367-371
2 O2:H2O and HF:H2O. The analysis of the etched samples by scanning electron microscopy (SEM) and scanning probe microscopy (SPM) indicates
that an array of square holes having well-defined patterned structures and clean substrate surfaces were obtained. The X-ray
photoelectron spectroscopy (XPS) analysis indicates that the SiC samples etched by VUV-266 nm multiwavelength laser have a similar
stoichiometry after chemical post-treatment as the virgin SiC. The mechanism of high-quality ablation using VUV-266 nm multiwavelength
laser is discussed in comparison with ablation using 266 nm single wavelength. The chemical post-treatment contributes to
removing the residues from the laser photolysis of SiC.
Received: 26 August 1996/Accepted: 17 October
1996 相似文献
75.
Jiro Murata 《Czechoslovak Journal of Physics》2002,52(3):C125-C134
An polarized hadron collider experiment must have a great discovery potential for a search of physics beyond the standard model. Experimental data of various symmetry tests at RHIC are going to be obtained within a few years. The author developed a simulation tool, studying a sensitivity of hunting contact interaction at RHIC by measuring parity violating spin asymmetries. 相似文献
76.
77.
78.
Akon Higuchi Masatomo Abe Jiro Komiyama Toshiro Iijima 《Journal of membrane science》1984,21(2):113-121
Permeabilities and diffusion coefficients of various gases, Ar, N2, O2, CO2, CH4, C2H4, C3H8 and C4H10, were measured for Water-swollen gel cellophane membranes. No dependence of permeabilities on gas pressure below 1 atm was found. It was observed that the permeability coefficients were not related linearly to the coefficients in bulk water. For the two states of water in the membrane, an analytical method is presented to estimate the diffusion coefficients and the solubilities in free water and non-freezing water. It was found that the diffusion coefficients in non-freezing water were lower than those in free water, and the solubilities in non-freezing water were higher than in free water for all gases studied except CO2 and C2H4, which gave reverse results. 相似文献
79.
80.
Palladium-catalyzed carbonylation of 3,5-dimethoxybenzyl chloride (13) with benzyl 7-hydroxyoctanoate (12) afforded benzyl 7-(3,5-dimethoxyphenylacetoxy)octanoate (6) in 70% yield, which is the precursor of Curvularin (4). The ester (12) was easily prepared from the butadiene telomer obtained by the palladium-catalyzed reaction of butadiene with acetic acid. 相似文献